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Biomedical subjects

R E Harbaugh

Publications and source records attributed to R E Harbaugh.

At least 55 records · Page 3Linked to original sources

Administration of intravenous urea and normal saline for the treatment of hyponatremia in neurosurgical patients.

Hyponatremia frequently complicates the care of neurosurgical patients and requires prompt effective therapy. These patients commonly fulfill the laboratory criteria of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) or cerebral salt wasting; the classification depends on the volume status of the patient. The authors have been dissatisfied with the standard therapy of fluid restriction for the critically ill neurosurgical patient because of 1) slow rates of sodium correction; 2) poor applicability in patients requiring multiple intravenous medications and/or nutritional support; and 3) possible dangers of inducing or enhancing cerebral ischemia in patients who already may be fluid-depleted. Reported successes in the treatment of hyponatremia due to SIADH by administration of urea and normal saline led to the authors' routine use of this therapy for hyponatremic neurosurgical patients. A retrospective review of an 18-month period revealed 48 patients (3% of all neurosurgical inpatients) with hyponatremia from various causes who received 62 treatments of urea and normal saline. Treatment consisted of 40 gm urea dissolved in 100 to 150 ml normal saline as an intravenous drip every 8 hours and an intravenous infusion of normal saline at 60 to 100 ml/hr for 1 to 2 days. The mean pretreatment serum sodium level (+/- standard deviation) was 130 +/- 3 mmol/liter (range from 119 to 134 mmol/liter). There was a significant mean posttreatment elevation to 138 +/- 4 mmol/liter (range 129 to 148 mmol/liter) (p less than 0.001, Student's t-test). Average daily fluid intake and output on treatment days were 2719 +/- 912 and 2892 +/- 1357 ml, respectively. There were no treatment complications in this group. It is concluded that urea and saline administration results in a rapid, safe, and effective correction of hyponatremia, making this method superior to fluid restriction in many neurosurgical patients.

Blood Urea Nitrogen↗

Intracerebroventricular bethanechol chloride infusion in Alzheimer's disease. Results of a collaborative double-blind study.

The use of intracerebroventricular bethanechol chloride infusion in patients with Alzheimer's disease was first reported in 1984. An initial trial in four patients demonstrated the feasibility of this approach for cholinergic drug delivery to the brain, but objective improvement in cognitive function was not documented. A collaborative placebo-controlled double-blind crossover study has now been carried out in 49 patients with biopsy-documented Alzheimer's disease. The results demonstrate a statistical improvement in Mini-Mental State scores and significantly slower performance on Trails A testing during drug infusion. Other neuropsychological test scores were not similarly affected. The degree of improvement was not sufficient to justify further treatment of Alzheimer's disease patients by intracerebroventricular infusion of bethanechol chloride. The drug delivery system used in the study was well tolerated, with two irreversible complications in more than 50,000 patient days.

Alzheimer Disease↗

Intracerebroventricular bethanechol chloride administration in Alzheimer's disease.

In June 1983 we began evaluating intracerebroventricular (ICV) cholinergic drug infusion in patients with biopsy-documented Alzheimer's disease (AD). An initial trial in four patients showed this treatment approach to be feasible, but objective improvement in cognitive or social function was not documented. A double-blind, placebo-controlled crossover study involving a larger number of patients has since been done. The results of this study, presented here, document a statistically significant improvement in some neuropsychological test results during periods of drug infusion. However, the degree of improvement is not sufficient to justify further treatment with the presently available drug, bethanechol chloride.

Aged↗

Encephalomeningocele presenting with spontaneous cerebrospinal fluid rhinorrhea in an elderly man: case report.

The case of a patient with spontaneous cerebrospinal fluid (CSF) rhinorrhea from an intranasal encephalomeningocele is presented. The case is unusual in that the patient was entirely asymptomatic until the age of 65, when copious CSF rhinorrhea developed without trauma or operation as an inciting event. The pertinent literature is reviewed, and no identical case has been found.

Aged↗

Use of implantable pumps for central nervous system drug infusions to treat neurological disease.

Increasing knowledge of the neurochemical aspects of central nervous system function raises the possibility of treating neurological disease by the appropriate manipulation of neurotransmitters, neuromodulators, and neurohormones. Clinical application of this knowledge has been inhibited, however, by long-standing problems with drug delivery to the central nervous system (CNS). The availability of implantable drug infusion pumps and stereotactic catheter placement techniques may overcome many of these problems. The problems of drug delivery to the brain and the present and potential uses of implantable drug pumps for neurological disease are discussed. In addition, the relationship between CNS drug infusion and neural tissue transplantation is briefly reviewed.

Brain Neoplasms↗

External ventricular drainage for initial treatment of neonatal posthemorrhagic hydrocephalus: surgical and neurodevelopmental outcome.

Thirty-seven infants were treated for posthemorrhagic hydrocephalus (PHH) with external ventricular drainage (EVD) in 1977-1985. The mean age at EVD placement was 13 days; the mean duration of drainage was 21 days, and an average of 1.8 drains was used per patient. Complications were apnea (10%), hemorrhage (8%) and ventriculitis (6%). Ten infants died from pulmonary disease unrelated to the surgery. Thirty-two percent of the survivors did not require a permanent shunt. Neurodevelopmental outcome was evaluated at a mean age of 38 months. Eighteen of the twenty-seven survivors (67%) had normal cognitive function, 3 had borderline and 6 (22%) had moderate to profound mental retardation. Nine of the children (33%) had a normal neuromuscular exam. One child had mild, 11 had moderate and 6 had severe cerebral palsy. Four children had serious visual impairment. The worst outcomes were in the children with parenchymal or large intraventricular hemorrhages.

Cerebral Hemorrhage↗

Intracerebroventricular cholinergic drug administration in Alzheimer's disease: preliminary results of a double-blind study.

In June 1983, we began evaluating intracerebroventricular (ICV) cholinergic drug infusion in patients with biopsy-documented Alzheimer's disease (AD). An initial trial in four patients showed this treatment approach to be feasible, but objective improvement in cognitive or social function was not documented (Harbaugh et al., 1984; Harbaugh, 1986). A double-blind, placebo-controlled crossover study involving a larger number of patients has since been done. The results of this study, presented here, document a statistically significant improvement in some cognitive test results during periods of drug infusion. However, the clinical applicability of this treatment approach is still questionable. A collaborative, double-blind study evaluating activities of daily living and cognitive test results during drug and placebo infusion is presently underway and should better define the safety and efficacy of this treatment approach for patients with AD.

Aged↗

Direct cerebrospinal fluid infusion of bethanechol chloride in Alzheimer's disease: use of an implantable continuous infusion device.

Recently, investigation into an experimental treatment for patients with Alzheimer's disease has begun utilizing surgical implantation of a continuous infusion device to deliver a muscarinic agonist, bethanechol chloride, directly into the cerebrospinal fluid (CSF). The nurse research assistant has been very active in this study being involved in patient evaluation, preoperative and postoperative patient education, collection of data, and refill of the infusion device. The neurosurgical nurse also plays an active role in patient education, immediate preoperative and postoperative care, and careful observation and recording of patient behavior and general well-being. Success of continued research based on this protocol will be enhanced by the contributions of the nurse research assistant and neurosurgical nurse familiar with the study and with her/his anticipated role.

Activities of Daily Living↗

Continuous drug delivery by an implantable pump.

Continuous infusion of drugs via an implantable infusion system offers advantages that are not available with other methods of drug delivery. For patients who require frequent drug injections, a continuous drug level, or high local concentrations, an implantable pump may assure compliance, comfort, and an improved therapeutic response. This method of drug delivery has been shown to be reliable and well tolerated by patients in numerous clinical trials. For hospice care professionals, familiarity with the mechanism of drug delivery and the various approved and experimental uses of the implantable pump will in all likelihood become increasingly important. At the present time regional infusion chemotherapy and intraspinal narcotic infusion for cancer pain seem to be most frequently encountered in a hospice setting. However, other uses for these implantable infusion systems are rapidly being developed, and this means of drug delivery probably will become more common in the next few years. One of the goals of continuous drug infusion by implantable pumps--optimal medical care without confining the patient to a hospital bed--is eminently compatible with the philosophy of hospice care.

Equipment and Supplies↗

Preliminary report: intracranial cholinergic drug infusion in patients with Alzheimer's disease.

After toxicity studies in dogs, a preliminary feasibility trial of the continuous intracranial infusion of a muscarinic agonist was begun in four patients with biopsy-documented Alzheimer's disease. During the last 8 months, a totally implantable infusion system has been used to deliver bethanechol chloride into the cerebrospinal fluid of these patients at doses of 0.05 to 0.7 mg/day. Complications have been few and resolved spontaneously or were easily reversible. The subjective response to this treatment has been encouraging, with reports of improved cognitive and social function during drug infusion and a return to base line function with single-blind saline placebo infusions. Obviously, further evaluation will be necessary to demonstrate the efficacy of this treatment, and a double-blind placebo-controlled crossover trial is now being done. However, we think the preliminary results are encouraging and warrant the consideration of this approach as a potential treatment in patients with Alzheimer's disease.

Aged↗

Hemangioma calcificans. Case report.

A 44-year-old woman presented with intraventricular hemorrhage and a calcified avascular mass lesion in the anterior third ventricle. This lesion proved to be a densely calcified variant of cavernous hemangioma, namely, hemangioma calcificans. Twelve previous cases of this lesion have been reported in the neurosurgical literature. Association with spontaneous intraventricular hemorrhage has not been previously reported. The clinical presentation, radiological appearance, surgical findings, and histopathology of this lesion are discussed and a brief review of the literature is presented.

Adult↗

The false fontanel.

In the neonate, palpation of the anterior fontanel is recognized as a simple and reliable means for estimating intracranial pressure. With closure of the fontanel this aspect of the clinical examination is lost. The authors report a series of 15 shunted infants and children in whom a false fontanel was created by making a 2-cm craniectomy in the right parietal region and excising the underlying internal pericranium. This produces a cranial opening which, like the anterior fontanel, can be used for palpation and real-time ultrasound imaging of the brain. By removing the internal pericranium, reossification of the defect is delayed by more than 12 months. Sparing the dura propria avoids the risks of cerebrospinal fluid leak or brain herniation into the cranial window. This procedure is reported to be simple, reliable, and of value in assessing shunt function in hydrocephalic infants and young children. An illustrative case report is presented.

Cerebrospinal Fluid Shunts↗